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OS/2 Shareware BBS: 35 Internet
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35-Internet.zip
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rsync221.zip
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fileio.c
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C/C++ Source or Header
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1999-03-04
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/*
Copyright (C) Andrew Tridgell 1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
File IO utilities used in rsync
*/
#include "rsync.h"
static char last_byte;
static int last_sparse;
extern int sparse_files;
int sparse_end(int f)
{
if (last_sparse) {
do_lseek(f,-1,SEEK_CUR);
return (write(f,&last_byte,1) == 1 ? 0 : -1);
}
last_sparse = 0;
return 0;
}
static int write_sparse(int f,char *buf,int len)
{
int l1=0,l2=0;
int ret;
for (l1=0;l1<len && buf[l1]==0;l1++) ;
for (l2=0;l2<(len-l1) && buf[len-(l2+1)]==0;l2++) ;
last_byte = buf[len-1];
if (l1 == len || l2 > 0)
last_sparse=1;
if (l1 > 0)
do_lseek(f,l1,SEEK_CUR);
if (l1 == len)
return len;
if ((ret=write(f,buf+l1,len-(l1+l2))) != len-(l1+l2)) {
if (ret == -1 || ret == 0) return ret;
return (l1+ret);
}
if (l2 > 0)
do_lseek(f,l2,SEEK_CUR);
return len;
}
int write_file(int f,char *buf,int len)
{
int ret = 0;
if (!sparse_files)
return write(f,buf,len);
while (len>0) {
int len1 = MIN(len, SPARSE_WRITE_SIZE);
int r1 = write_sparse(f, buf, len1);
if (r1 <= 0) {
if (ret > 0) return ret;
return r1;
}
len -= r1;
buf += r1;
ret += r1;
}
return ret;
}
struct map_struct *map_file(int fd,OFF_T len)
{
struct map_struct *ret;
ret = (struct map_struct *)malloc(sizeof(*ret));
if (!ret) out_of_memory("map_file");
ret->map = NULL;
ret->fd = fd;
ret->size = len;
ret->p = NULL;
ret->p_size = 0;
ret->p_offset = 0;
ret->p_len = 0;
#ifdef USE_MMAP
len = MIN(len, MAX_MAP_SIZE);
ret->map = (char *)do_mmap(NULL,len,PROT_READ,MAP_SHARED,fd,0);
if (ret->map == (char *)-1) {
ret->map = NULL;
} else {
ret->p_len = len;
}
#endif
return ret;
}
char *map_ptr(struct map_struct *map,OFF_T offset,int len)
{
int nread;
if (len == 0)
return NULL;
if (len > (map->size-offset))
len = map->size-offset;
#ifdef USE_MMAP
if (map->map) {
if (offset >= map->p_offset &&
offset+len <= map->p_offset+map->p_len) {
return (map->map + (offset - map->p_offset));
}
if (munmap(map->map, map->p_len) != 0) {
rprintf(FERROR,"munmap failed : %s\n", strerror(errno));
exit_cleanup(RERR_MALLOC);
}
/* align the mmap region on a nice boundary back a bit from
where it is asked for to allow for some seeking */
if (offset > 2*CHUNK_SIZE) {
map->p_offset = offset - 2*CHUNK_SIZE;
map->p_offset &= ~((OFF_T)(CHUNK_SIZE-1));
} else {
map->p_offset = 0;
}
/* map up to MAX_MAP_SIZE */
map->p_len = MAX(len, MAX_MAP_SIZE);
map->p_len = MIN(map->p_len, map->size - map->p_offset);
map->map = (char *)do_mmap(NULL,map->p_len,PROT_READ,
MAP_SHARED,map->fd,map->p_offset);
if (map->map == (char *)-1) {
map->map = NULL;
map->p_len = 0;
map->p_offset = 0;
} else {
return (map->map + (offset - map->p_offset));
}
}
#endif
if (offset >= map->p_offset &&
offset+len <= map->p_offset+map->p_len) {
return (map->p + (offset - map->p_offset));
}
len = MAX(len,CHUNK_SIZE);
if (len > (map->size-offset))
len = map->size-offset;
if (len > map->p_size) {
if (map->p) free(map->p);
map->p = (char *)malloc(len);
if (!map->p) out_of_memory("map_ptr");
map->p_size = len;
}
map->p_offset = offset;
map->p_len = len;
if (do_lseek(map->fd,offset,SEEK_SET) != offset) {
rprintf(FERROR,"lseek failed in map_ptr\n");
exit_cleanup(RERR_FILEIO);
}
if ((nread=read(map->fd,map->p,len)) != len) {
if (nread < 0) nread = 0;
/* the best we can do is zero the buffer - the file
has changed mid transfer! */
memset(map->p+nread, 0, len - nread);
}
return map->p;
}
void unmap_file(struct map_struct *map)
{
#ifdef USE_MMAP
if (map->map) {
munmap(map->map,map->p_len);
map->map = NULL;
}
#endif
if (map->p) {
free(map->p);
map->p = NULL;
}
memset(map, 0, sizeof(*map));
free(map);
}